The question needs to be made relative to the OPs definition of outdated, since you cannot apply something as black and white as a dictionary definition because it doesn't take into consideration the context/scenario.
If the question is; can this still play the latest titles with all applicable features enabled, the answer is that the 1080 Ti is now outdated and cannot do this because it cannot use DLSS/RT.
If the question is; is this cards raw processing power still relevant in today's market, the answer is that the 1080 Ti is not outdated and can handle most tasks you could possibly expect of a high end consumer card.
For me the OP hasn't made the definition clear enough for us to argue over it, IMHO.